TY - JOUR
T1 - Composition and structure of an iron-bearing, layereddouble hydroxide (LDH) - Green rust sodium sulphate
AU - Christiansen, Bo C.
AU - Balic Zunic, Tonci
AU - Petit, Pierre-Olivier
AU - Frandsen, Cathrine
AU - Mørup, Steen
AU - Geckeis, Horst
AU - Katerinopoulou, Anna
AU - Stipp, Susan Louise Svane
PY - 2009
Y1 - 2009
N2 - Mixed-valent Fe(II),Fe(III)-layered hydroxide, known as green rust, was synthesized from slightly basic, sodium sulphate solutions in an oxygen-free glove box. Solution conditions were monitored with pH and Eh electrodes and optimized to ensure a pure sulphate green-rust phase. The solid was characterised usingMo¨ssbauer spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the solution from which the green rust precipitated was established by mass and absorption spectroscopy. The sulphate form of green rust is composed of brucite-like layers with Fe(II) and Fe(III) in an ordered distribution. The interlayers contain sulphate, water and sodium in an arrangement characteristic for the nikischerite group. The crystal structure is highly disordered by stacking faults. The composition, formula and crystallographic parameters are: NaFe(II)6Fe(III)3(SO4)2(OH)18•12H2O, space group P-3, a = 9.528(6)Å, c = 10.968(8)Å andZ = 1. Green rust sodium sulphate, GRNa,SO4, crystallizes in thin, hexagonal plates. Particles range from less than 50 nm to 2 µm in diameter and are 40 nm thick or less. The material is redox active and reaction rates are fast. Extremely small particle size and high surface area contribute to rapid oxidation, transforming green rust to an Fe(III)-phase within minutes.
AB - Mixed-valent Fe(II),Fe(III)-layered hydroxide, known as green rust, was synthesized from slightly basic, sodium sulphate solutions in an oxygen-free glove box. Solution conditions were monitored with pH and Eh electrodes and optimized to ensure a pure sulphate green-rust phase. The solid was characterised usingMo¨ssbauer spectroscopy, X-ray diffraction, scanning electron microscopy and atomic force microscopy. The composition of the solution from which the green rust precipitated was established by mass and absorption spectroscopy. The sulphate form of green rust is composed of brucite-like layers with Fe(II) and Fe(III) in an ordered distribution. The interlayers contain sulphate, water and sodium in an arrangement characteristic for the nikischerite group. The crystal structure is highly disordered by stacking faults. The composition, formula and crystallographic parameters are: NaFe(II)6Fe(III)3(SO4)2(OH)18•12H2O, space group P-3, a = 9.528(6)Å, c = 10.968(8)Å andZ = 1. Green rust sodium sulphate, GRNa,SO4, crystallizes in thin, hexagonal plates. Particles range from less than 50 nm to 2 µm in diameter and are 40 nm thick or less. The material is redox active and reaction rates are fast. Extremely small particle size and high surface area contribute to rapid oxidation, transforming green rust to an Fe(III)-phase within minutes.
KW - Faculty of Science
U2 - 10.1016/j.gca.2009.03.032
DO - 10.1016/j.gca.2009.03.032
M3 - Journal article
SN - 0016-7037
VL - 73
SP - 3579
EP - 3592
JO - Geochimica et Cosmochimica Acta
JF - Geochimica et Cosmochimica Acta
IS - 12
ER -